I use Windows 8.1 Pro 64 bit and IE11. I have two personal certificates (with private key) of mine in the system certificate store. They are both set to require a password before they can be used.

This worked until a few days ago. Then I noticed that one of them is accessible without a password. How could that happen?

What I normally do is:

  • I open a HTTPS website that requires certificate auth
  • the dialog pops up to select a certificate (only one is offered, based on the CA, each of my certs are from different CAs)
  • after I select it, another system dialog appears, asking to grant or deny access to the certificate and for granting, I must enter the password
  • after entering the correct password, the website loads

This worked like this for both of the certificates (each used on a different website). But recently, one certificate does not require the password any more. I can just select it and use it to access the website. The other still requires the password.

To check my memory is not playing tricks with me, I restored a system image backup a few month old. It has Windows 8 Pro and IE10. There both certificates ask for a password. (I upgraded that system to Windows 8.1 via the Windows Store).

I don't see a way to change the security level of certificates after they are imported, so I did not do it myself and the forget about it.

I can re-import the certificate and set a password for it, but the question is, how did this happen? I checked the PC for malware (booting from a USB key: HBCD and Ubuntu) and found nothing.

  • I installed Google Chrome and it behaves the same: one certificate requires the password, the other is usable without any password. Nov 27, 2013 at 15:17

2 Answers 2


Security levels on private keys in Windows are a rather complex subject; in particular, there are options for activating or deactivating the password, and for caching the password in memory. See this blog post for an introduction. Notably, the protection level for a given key is not intrinsically immutable; it may be changed. Possibly, Windows 8.1 changed some default behaviour; or maybe some action on your part, that you do not remember (that's not a blame; there are way too many popups in Windows to realistically expect to remember them all and miss none), changed the protection level at a time which fortuitously happened to be after your last pre-8.1 backup. In any case, you could go inspect the current status of your private keys and change it according to your wishes.

  • Any idea how to change the status of the keys? I just looked and there are no options for any changes. Mar 25, 2014 at 21:22

What I saw in Windows 8 is that you only have to enter your password once per session. Windows remembers it. If you restart the computer however you will be asked again for the password...

Anyway I always thought Microsoft treats the security of our private keys very lightly. Using metaphore, it is as if they said: "We put a lock on your door, that is secure, so we can store the key on a nail in the wall. And if you really want top security hide it under the doormat"

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .